采用单因素实验方法探讨了电流密度、温度、pH 值、搅拌速度对电沉积Cr-Al2O3 纳米复合镀的影响;并用L9(34)正交实验方法,确定了主络合剂、辅助络合剂、分散剂、AlCl3·6H2O 对纳米复合镀层外观、厚度以及纳米氧化铝含量的影响,确定了最佳镀液配方,并利用扫描电镜、能谱仪和硬度测试仪测试了所得镀层的形貌和性能。结果表明:在最佳工艺条件下,以主络合剂18.9g/L,辅助络合剂3.85g/L,分散剂质量分数2%,结晶氯化铝12g/L所得的镀层厚度可达到13.93μm,纳米氧化铝的质量分数平均可达到10.90%,镀层的显微硬度可达到867.9HV。

Through single-factor experiment, effects of current density, pH value, temperatrue,stirring speed on Cr-Al2O3 coatings were studied to obtian a suitable scopes. Orthogonal experiment L9(34) was designed to ascertain the influence of main complexing agent, auxiliary complexing agent, dispersant and AlCl3·6H2O on the thickness, appearance and the content of Al.Surface morphology, composition and microhardness of coatings were characterizated through using SEM, EDS and hardness tester respectively. Results revealed that under the optimized process condition and the optimized bath recipes namely: main complexing agent 18.9g/L, auxiliary complexing agent 3.85g/L, dispersant 2% and AlCl3·6H2O 12g/L, the Cr-Al2O3 composite coatings possess the thickness of 13.93 μm, the proportion of Al 10.90% and high microhardness of 867.9 HV.